US President Barack Obama is expected to use his upcoming speech at the largest-ever gathering of America’s most influential pro-Israel lobby to reassure the Jewish state of his administration’s commitment to preventing Iran from acquiring nuclear weapons.

Recent news reports and statements by US officials suggest that the White House is in discord with Jerusalem over the right course of action regarding the Iranian threat. But Obama is widely expected to try to calm fears that Israel is alone in its quest to stop the Islamic Republic’s nuclear ambitions. According to well-informed sources, Obama intends to reiterate that his administration is considering all possible options – including a military strike – to stop Tehran’s race to a nuclear weapons capability.

Obama will address the annual policy conference of the Washington-based American Israeli Public Affairs Committee at its opening session on Sunday. Some 13,000 participants are expected, making it the largest conference in the organization’s nearly 50-year-old history.

US Defense Secretary Leon Panetta will also address the delegates, marking the first time that both a sitting US president and defense minister will appear at an AIPAC conference, which further underlines the administration’s determination to demonstrate goodwill to the Israeli leadership and its supporters.

According to sources familiar with the issue, Obama’s address will adopt a tone similar to the one of a speech he gave at the United Nations’ General Assembly, considered one of his most pro-Israel speeches.

“Let us be honest with ourselves: Israel is surrounded by neighbors that have waged repeated wars against it,” Obama said last September. “Israel, a small country of less than eight million people, look[s] out at a world where leaders of much larger nations threaten to wipe it off of the map.”

During that speech, Obama did not say what he intends to do if sanctions fail to convince the Iranian regime to abandon its nuclear aspirations. While it is unlikely that he will announce any concrete plans for the scenario of an Iran unwilling to drop its bid for nuclear weapons, it is expected that he will assure the delegates that “all options remain on the table.”

Speaking at a daily press briefing on Tuesday, White House press secretary Jay Carney confirmed that the issue of Iran is going to come up in Obama’s AIPAC address. “His position is what it has been, which is that we will take no option off the table, but we believe that there is time and space to allow for a diplomatic resolution through the pressure that we are asserting on Tehran through sanctions and other means with our international partners.”

President Shimon Peres and Prime Minister Netanyahu will also address the AIPAC conference, and much ink has been spilled about what the two leaders might say in their meetings with Obama.

Haaretz, for instance, reported that the prime minister “wants Obama to make further-reaching declarations than the vague assertion that ‘all options are on the table.’” Quoting anonymous Israeli officials, the paper claimed that Netanyahu intends to pressure Obama into announcing that he is preparing for a military operation if Iran crosses certain “red lines.”

America has made, and continues to make, statements to similar effect all the time, with senior leaders reiterating that “all options are on the table” to stop Iran from acquiring nuclear weapons. Speaking at a Jerusalem conference last week, Washington’s ambassador to Tel Aviv, Dan Shapiro, for instance, said that while economic sanctions against Tehran are America’s “preferred strategy,” all other options are on the table – “and more than that, the necessary planning has been done to ensure those options are actually available if at any time they become necessary.”

Meanwhile, Netanyahu’s aides are tight-lipped about what’s on the agenda. One government official told The Times of Israel that Netanyahu’s AIPAC speech, scheduled for Monday night, will “break new ground” in terms of Israel’s policy. He declined to detail. And other sources were skeptical.

While Obama, according to some sources, will deliver a speech supportive of Israel because he needs to be on the good side of the pro-Israel crowd in the US – especially since his potential Republican rivals for the presidency will address the AIPAC delegates on Monday – it is reasonable to assume that he is unimpressed by the prospect of being pressured by Netanyahu, the sources said. “Our policy remains exactly what it was,” Jay Carney, the White House press secretary, said. “We are committed, as Israel is, to preventing Iran from acquiring a nuclear weapon.”

Netanyahu last week ordered his ministers to stop talking about Iran — at around the same time as Defense Minister Ehud Barak was discussing the issue at length in a Channel 2 interview. Barak indicated that Israel has a viable military option against Iran, even if acting alone, and said that however complex it might be to grapple with Iran today, it would be still more problematic later on.

Since the weekend, however, ministers and officials in Jerusalem do seem to have quietened down somewhat, and media speculation has filled the vacuum. Did Peres plan to tell Obama he is against an Israeli strike on Iran, as one report had it? The president is adamant that this is not the case. Did Martin Dempsey, the chairman of the US Joint Chiefs of Staff, try to dissuade Israel from an attack on Iran? Dempsey says no.

Since declaring on a visit to Cyprus last week that sanctions on Iran were not working — an assessment from which Secretary of State Hillary Clinton publicly differs almost daily — Netanyahu himself has been notably quiet about his strategy regarding the Iranian threats.

What is unarguable is that the level of coordination between Israel and the US is unprecedented: Ehud Barak is in the US already, and met Wednesday with Panetta and Pentagon officials, with National Security Adviser Tom Donilon, and with Vice President Joe Biden at the White House. Mossad chief Tamir Pardo was there in January. Netanyahu heads off on Thursday — via Canada. Peres and Obama will have one-on-one time on Sunday. Recent weeks have seen Panetta, Dempsey, Donilon and national intelligence chief James Clapper, among others, holding consultations in Jerusalem.

The frequency of such high-level visits is thoroughly atypical. Beyond coordination, however, the open question is how much tension and disagreement it reflects regarding the specifics of thwarting Iran.

Among the pundits weighing in, Eytan Gilboa, an expert on Israeli-American relations from Bar-Ilan University, believes that Netanyahu is first and foremost going to ask Obama for a clarification regarding his stance vis-à-vis Iran.

“The message that the Americans are sending is that Iran is a rational actor that has not yet decided whether to build nuclear weapons, that sanctions work and that there is no room now for military action,” Gilboa said. “From the Israeli perspective, all of these assertions are complicated, especially the fact that they take a military option off the table.”

Netanyahu himself isn’t clear about the American position, Gilboa suggested. “He is going to ask Obama what he means when he says that the US says that all options are on the table but then rules out an attack? And what are you going to do if the sanctions fail? One of the main goals of the meeting is simply to clarify, to make sure the two side are broadcasting on same wavelengths.”

After their meeting on Monday, Obama and Netanyahu are expected to release a joint statement about the Iranian issue. It will likely highlight the areas on which the two leaders agree – that Iran must not be allowed to acquire a nuclear weapon and that the two sides agree to intensify cooperation to achieve that goal – and ignore questions on which there is disagreement, such as what it would take for either nation to launch an attack.

While Israel and its supporters are likely to enjoy listening to Obama’s speech on Sunday, therefore, they may well be none the wiser regarding the specifics of America’s own position on thwarting Iran or the question of its support for an Israeli strike.